Optimizing hybrid inverter system

ABSTRACT

The present invention relates to resiliency in photovoltaically produced power generation and utilization. This invention comprises a system of elements that combine to minimize the cost and complexity of a backup-capable solar power system. An element of this system is a prior-art balancer-based photovoltaic panel power optimizer whose power electronics are time-shared to allow an array of battery modules to power or provide supplemental or surge power to an inverter. Further elements of the system provide for rapid and low-cost installation, reliability, and easy and safe maintenance.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 62/933,494, filed Nov. 10, 2019, the entire contents ofwhich are incorporated herein by reference for all purposes.

BACKGROUND

String inverters have a limited ability to function as anuninterruptable power system because, with their fixed photovoltaic (PV)power and without substantial internal power storage, they often cannotsupply surge power needed to start large appliances such asrefrigerators and air conditioners. To solve this problem, some priorart inverters supplement PV power with battery-stored power to boostoutput. Some such inverter systems can store power during the day andprovide it to the grid or a local load such as a household at a latertime. It is also known in the art to implement an automatic transferswitch to an alternative power source such as an inverter or generatorwhen the grid voltage is out of a specified range. It is known in theart that a local load will often comprise a number of subloads. Herein,a subload comprises one of a plurality of circuits connected in parallelto a power source. Subloads of different urgency or priority and choicesmust often be made as to what loads to power when grid power is notavailable.

In prior-art systems this prioritization is performed using a sub-panelthat is connected to a statically determined priority subset of thesubloads or power outlets. In some prior-art systems the sub-panel isconnected to the main by an automatic transfer switch such that, whengrid power is unstable or unavailable, only the subloads connected tothe sub-panel are energized by the alternate power source. Thisarrangement has the drawback of requiring a static set of subloads andpower outlets to be determined and wired. The installation and wiring ofa subpanel for this purpose may entail undesirable hardware and laborcosts. The limitation of a static set of subloads may entail undesirablecomplexity and limitations during an outage.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows a diagram of a complete hybrid inverter optimizer systemaccording to various embodiments.

FIG. 1B shows a front view of an embodiment of an assembled hybridinverter according to various embodiments.

FIG. 1C shows a side view of the hybrid inverter according to variousembodiments.

FIG. 1D shows a front view of an inverter during maintenance accordingto various embodiments.

FIG. 1E shows a side view of an inverter during maintenance according tovarious embodiments.

FIG. 1F shows a front view of an inverter during maintenance accordingto various embodiments.

FIG. 1G shows a side view of an inverter during maintenance according tovarious embodiments.

FIG. 1H shows an inverter undergoing maintenance having a detachedbattery module according to various embodiments.

FIG. 1I shows an inverter with battery modules removed according tovarious embodiments.

FIG. 1J shows an isometric view of an inverter undergoing maintenanceaccording to various embodiments.

FIG. 2A shows a simplified schematic diagram of a battery charge controlcircuit according to various embodiments.

FIG. 2B shows a plurality of battery charge control circuits accordingto various embodiments.

FIG. 3A shows a schematic diagram of a variant of a circuit according tovarious embodiments.

FIG. 3B shows a schematic diagram of a variant of a circuit according tovarious embodiments.

FIG. 3C shows a schematic diagram of a variant of a circuit according tovarious embodiments.

FIG. 3D shows a schematic diagram of a variant of a circuit according tovarious embodiments.

FIG. 3E shows a schematic diagram of a variant of a circuit according tovarious embodiments.

FIG. 3F shows a schematic diagram of a variant of a circuit according tovarious embodiments.

FIG. 4 shows an array of four circuits according to various embodiments.

FIG. 5 shows a plurality of switches or a ganged switch according tovarious embodiments.

FIG. 6 shows an array of circuits according to various embodiments.

FIG. 7A shows a front view of a battery module according to variousembodiments.

FIG. 7B shows a side view of a battery module according to variousembodiments.

FIG. 7C shows a back view of a battery module according to variousembodiments.

FIG. 8 shows a schematic diagram of a battery charge management circuitaccording to various embodiments.

FIG. 9A shows a side view of a capacitor module according to variousembodiments.

FIG. 9B shows an offset view of the capacitor module according tovarious embodiments.

FIG. 9C shows a side view of a capacitor module in a detached configuredaccording to various embodiments.

FIG. 9D shows an offset view of the capacitor module in the detachedconfiguration according to various embodiments.

DETAILED DESCRIPTION

Herein a L1 is a current-carrying alternating current (AC) line, L2 is asecond current-carrying AC line whose voltage is out of phase with thatof L1. N is a current-carrying AC line, normally called a neutral linesubstantially at the average voltage of L1 and L2.

Where used, the neutral (N) power circuit is normally produced viainduction in a generator or transformer. If the connection to thisinductor is disconnected, a secondary means of establishing the neutralcircuit may be necessary to insert into the power circuit. Anautotransformer is commonly used to perform this function. In someembodiments of the present invention, an autotransformer is staticallywired to L1, L2, and N. This arrangement has the advantage ofsimplicity, but presents a parasitic load, even when it is not needed inthe circuit. Some embodiments of the present invention comprise a switchthat makes and breaks an electrical connection to an inductor. In someembodiments the inductor is an auto-transformer. In some embodiments theswitch is a 2-pole switch. In some embodiments, the poles switch L1 andL2, while N is statically connected to a center tap. In someembodiments, the poles switch either L1 or L2 and N, while the thirdcircuit is statically connected to an outer terminal of autotransformer.In some embodiments the switch comprises a circuit breaker that tripsbased on one or more of: over-current, over-temperature, under-voltage,over-voltage, cycle frequency. In some embodiments, the switch isactuatable. In some embodiments, the switch comprises a circuit breakeron a main or sub-panel. In some embodiments the circuit breakerautomation is performed by a motorized or solenoidally actuated switchinterface disposed to exert switching force toward both the ‘on’ and‘off’ position. In some embodiments, the switch interface contains anopening that is wide enough to allow a manual override of the switchposition. In some embodiments, the switch interface does not allow amanual disconnect. This prohibition may protect against serious voltagefaults if the autotransformer is switched off while there is noalternate means of establishing the neutral line. In some embodiments,the actuator of the switch comprises a switch microcontroller in digitalor analog communication with a second microcontroller. In someembodiments, the switch microcontroller senses the position oracquisition state of the switch. In some embodiments, the switchmicrocontroller senses one of more of: voltage, current, position,magnetic field, electrostatic field. In some embodiments the switchmicrocontroller's sensing of switch state is an interlock signalrequired by a microcontroller, possibly the same microcontroller, toenable operation of an inverter. In some embodiments of the presentinvention, the autotransformer switch is electronic, e.g., a solid-staterelay, MOSFET, BJT, IGBT, or other switch known in the art. In someembodiments the autotransformer switch is actuated automatically whenimproper voltage is detected between L1 or L2 and N. In someembodiments, the autotransformer is switched off automatically when thecurrent in the neutral line is below a threshold for an interval oftime. In some embodiments, the autotransformer switch may comprise arapid-acting over-voltage detection device, such as a MOV, TVS,avalanche diode, discharge cell, etc. as known in the art to maintainsafety for brief switch actuation periods and fault-detection latency.Some embodiments synchronize the actuation of the switch with one ormore of the AC-cycle voltage waveform, inductor current waveform,magnetic field, etc. Such synchronization may reduce line transientsproduced by abrupt current changes. In some embodiments, theautotransformer and switch are integrated with an inverter.

In some embodiments, the autotransformer, switch, and communicationmeans are housed in a separate enclosure. In some embodiments, one ormore of these elements are housed in a statically installed, stationarycomponent of a hybrid inverter system.

For safety, prior-art battery backup systems typically work at a batteryvoltage of 50 V or lower. This may have the disadvantage of requiringrelatively expensive interconnect conductors. Such systems typicallycomprise paralleled batteries, which can result in non-ideal charge anddischarge behavior for some batteries because of temperature, chemistry,age, or capacity differences. Some prior-art battery charge controllersemploy a ‘balancer’ circuit to adapt the charge and discharge current tooptimize each battery, but this arrangement may have the disadvantage ofexcessive cost.

Hybrid Inverter Optimizer

The present invention represents a comprehensive cost optimization of asolar-based uninterruptable power system that provides maximalflexibility to power subloads and outlets during an outage. The presentinvention comprises a PV string inverter as known in the art. In someembodiments, the string inverter is a massively interleaved inverter,featuring a high degree of power circuitry redundancy for faulttolerance. Some embodiments of the present invention further comprise abalancer having a bypass connection between at least two solar panelsthrough which current may pass so as substantially to maximize the powerharvest of more than one solar panel simultaneously. The conductorthrough with the current flows is herein called a ‘bypass cable.’

FIG. 1A shows a diagram of a complete hybrid inverter optimizer system100 according to an embodiment of the present invention. The hybridinverter system 102 comprises a substantially statically mounted orstationary unit 104, a light-weight, power module 106 containingpower-processing electronics, a gang 108 of battery modules, and acapacitor module 110. In some embodiments, high-reliability componentsand conventional electrician-installed components are housed in 104.Items that degrade over time such as batteries and electrolyticcapacitors are respectively housed in removable modules 108 and 106.Power electronics, which may be susceptible to component failure, arehoused in a removable module such that the mass of the componentry thatmust be replaced in the event of a loss of function is minimal. System112 is a PV array. Elements 114 and 116 are respectively anode-(positive) and cathode- (negative) side PV-panel-mounted cables. Element118 is a mated solar power connector, e.g., an MC4 connector as known inthe art. Element 120 is a connector between both genders of a solarconnector and a bypass cable 122. In some embodiments, the bypass cable122 is permanently connected. In some embodiments the bypass cable isbreakably connected. In some embodiments. The connector 120 furthercomprises one or more of the following in the connector contact region:a conductive paste, gel, powder, or grease, an anti-corrosion paste,gel, powder or grease, a water-proofing agent, a water gettering agent.Elements 126 and 128 are cables carrying the primary string current onthe positive and negative side, respectively. System 130 is a bundle ofDC bypass and primary cables leading from the photovoltaic array.

In some embodiments, this cable bundle is sheathed in a material 132that may provide one or more of: insulation, UV-light-resistance, waterresistance, fire protection, animal, insect, and plant resistance,impact, crushing, and abrasion protection, aesthetics, facilitatedmounting to railing and structures, interior to exterior feedthroughs.Some embodiments comprise one or more of a mesh, metal, plastic,extrusion, clam-shell assembly, flexible assembly, tube, conduit. Someembodiments comprise an alternative means of bundling an array ofcables.

Element 134 is a feedthrough into the stationary housing 104. Element136 is a terminal block or breakable connector to the DC bundle 130.Element 138 is a link between the cable termini at 136 and feedthrough140 to power module 106. At least one breakable connection existsbetween element 138 and 140 or 140 and 106 to facilitate servicing ofthe power module 106. Element 138 may further comprise one or more of: aswitch, a rapid-shutdown shunt, a DC disconnect, mechanical and motionapparatus, circuit protection device.

Element 142 comprises AC circuits. In some embodiments these circuitsare L1, L2, and N. Element 144 is a terminal block or breakableconnection to the AC circuits. Element 146 links the connection 144 viafeedthrough 140 to the power module 106. A breakable connection existsto facilitate removal of the power module for servicing or replacement.Element 146 may further comprise one or more of an AC disconnect switch,mechanical and motion apparatus, a circuit protection device.

Some embodiments further comprise a transformer or autotransformer 148and link 150 to AC circuits. In some embodiments, 150 further comprisesa static or automatable switch or relay to make and break connections toAC circuits. Element 152 is a conduit or cable to a power panel, e.g., acircuit breaker 154 on a main panel. In some embodiments, element 152connects to a subpanel directly or through a circuit breaker.

Some embodiments of the present invention can provide backup power inthe event of a grid outage. To avoid back-powering the grid someembodiments further comprise a switch automator or switch-positionsensor 156. In some embodiments, 156 is installed over a servicedisconnect switch. In some embodiments, 156 is in communication (158)with a controller in the hybrid inverter. In some embodiments, 156 is incommunication (160) with a smart meter (162). In some embodiments,communication is wireless; in some embodiments it is wired. In someembodiments, 156 further comprises a circuit that detects grid voltageand frequency even when the service disconnect switch is open.

Some embodiments of the present invention further comprise at least oneswitch automator 164 installed over a circuit breaker in a power panelor sub-panel 166. In some embodiments 164 communicates with a controllerover a wired or wireless communications link 168. Some embodimentsdynamically control loads by actuating one or more breaker.

Some embodiments of the present invention further comprise at least one‘smart outlet’ 170 that communicates with a controller via a wired orwireless communications link 172. Some embodiments dynamically controlloads by sending commands to one or more smart outlet. Some embodimentsfurther diagnose whether one or more circuit is drawing excessivecurrent by receiving data from one or more smart outlets.

FIG. 1B shows a front view 180 of an embodiment of an assembled hybridinverter, comprising stationary, statically-installed module 104, powermodule 106, battery module assembly 108, and capacitor module assembly110, according to an embodiment of the present invention. FIG. 1C showsa side view 184 of the hybrid inverter embodiment. The heat-generatingelements 106, 108, and 110 are disposed as a slender ‘cooling fin’ formaximally material efficient heat transfer to ambient.

FIGS. 1D and 1E respectively show front (186) and side (188) views of aninverter embodiment during maintenance, in which the capacitor moduleassembly 110 is detached from the power module.

FIGS. 1F and 1G respectively show front (190) and side (194) views of aninverter embodiment during maintenance, in which a battery moduleassembly shroud 191 is detached, revealing a physical battery isolator192 and array of battery modules 193. Some embodiments of physicalbattery isolators comprise a material that may prevent a battery firefrom spreading from one module to an adjacent one. In some embodimentsthis isolator is an array of tubes or channels in which the batterymodules are inserted. In some embodiments, this isolator is a corrugatedstructure wherein battery modules are nested in the corrugations. Insome embodiments, battery modules are nested in corrugations on bothsides of the corrugation. In some embodiments, this isolator is madefrom one or more of: steel, aluminum, fiberglass, epoxy, a UL94V-ratedplastic, a ceramic, a composite, a lamination. In some embodiments thisbattery isolator further comprises a stationary, statically installedstructural skeleton for enhanced rigidity.

FIG. 1H shows an embodiment 195 of an inverter undergoing maintenancehaving a detached battery module 196. FIG. 1I shows an embodiment 197from which all battery modules are removed from the isolator 192,allowing the power (106) and capacitor (110) modules to be detached fromthe stationary assembly 104. FIG. 1J shows an isometric view 199 of aninverter embodiment undergoing maintenance in which only the stationary,statically installed components remain. Element 140 is a feedthrough.The isolator 192 is shown with the battery modules removed in FIG. 1J.Additional static support and attachment components are not shown.

Balancer/Battery Management

Some embodiments of the present invention pass power through a bypasscable from a solar panel to a battery, some from a battery to a solarpanel, some pass power in both directions at different times. Someembodiments employ a non-isolated boost circuit, a non-isolated buckcircuit, or a non-isolated buck-boost circuit known in the art to chargea battery from a solar panel. Some embodiments employ a flyback orisolated converter to charge a battery. Some embodiments employ anon-isolated buck circuit, a non-isolated boost circuit, or anon-isolated buck boost circuit known in the art to supply current froma battery to a solar panel. Some embodiments employ a flyback orisolated converter to supply current from a battery to a solar panel.Some embodiments comprise a boost converter to charge a battery and abuck converter to discharge a battery, the buck converter and boostconverter sharing a switch that may act as a synchronous rectifier.

Some embodiments may charge a battery from an isolated power source. Insome embodiments, isolation is provided by one or more of the following:a capacitor, a coupled inductor, a photovoltaic cell. Some embodimentssupply isolated power for charging from one or more of: bypass currentfrom a bypass cable connected to a solar panel, power derived from an ACcircuit, power derived from a DC bus, power derived from a DC stringvoltage. In some embodiments the power circuitry is sized to be able tosubstantially charge a battery in one charge period comprising one ormore of: a solar day, the period before an inverter is started, alow-value-power interval, a period in which solar power would be netexported, a period in which solar power would be undervalued by autility, a period in which power from a utility is relativelyinexpensive, one day.

In some embodiments, battery power may be carried by current over abypass cable to increase the overall power efficiency of a PV string. Insome embodiments at some times, current flows in bypass cablesbidirectionally substantially to minimize the total efficiency losses ofthe power electronics. For example, if a single panel is underproducing, it may be more power efficient to boost its output bysupplemental power on a bypass line, than to draw excess production fromthe rest of the solar panels. In some embodiments, a controller employsan efficiency model that may also take into account battery capacity andcharge storage efficiency to calculate a substantially optimumcurrent-balance setting. In some embodiments, current flows in bypasscables to maximize the solar array power output while re-supplyingbattery power.

Some embodiments of the present invention can provide backup power atnight or in low solar illumination. In low light, some such embodimentsset the battery charge controller circuit to pull power from its batterymodule. In some embodiments, this drawing of power produces a voltagethat is communicated to the connected solar panel via current in abypass cable. In zero light, the solar panel is substantially a seriesarray of diodes that are forward biased by this voltage. According tothe diode equation, the forward current flowing through the panel, whichmay dissipate electrical power, depends substantially exponentially onthe ratio of the forward voltage to a threshold voltage. Someembodiments of the present invention maintain a low applied forward biasvoltage by one or more of: controlling a buck converter that draws powerfrom the battery module, drawing string current into the inverter, anddiverting current from the solar panel to an optimizer circuit thatdelivers bypass power to the inverter. In some embodiments, theoptimizer is architected so that its output power creates a pedestalvoltage for the inverter. In some embodiments, the optimizer isarchitected so that its output power creates or supplements ahigh-voltage bus for the inverter. In some embodiments, the measuredback-feeding of voltage to the panels produces a string voltage thatreduces required voltage rating or voltage stresses on a switch thatconverts between normal string operation and voltage-boost modeoperation.

Some embodiments comprise a diode or an electronic switch, a mechanicalswitch, a motorized switch, a relay, or solid-state relay, herein calleda ‘panel back-feed isolator.’ Some embodiments comprising an electronicswitch have a body diode disposed to prevent current from flowing fromthe battery discharge circuit to the otherwise connected solar panel. Apanel back-feed isolator comprising a switch or relay may allow power tobe back-fed to a panel and may reduce the forward voltage drop thatwould be otherwise incurred. A panel back-feed isolator according to thepresent invention may be physically located in one or more of thefollowing places: at a solar panel, in a bypass cable junction tee orwye, in a node along a bypass cable, at a terminal of a bypass cable, inthe stationary enclosure, in the wire terminal connector, in the powermodule, in the positive side of the bypass circuit, in the negative sideof the bypass circuit. In some embodiments, the panel back-feed isolatoris a ganged motorized switch, relay, or breakable connection. In someembodiments, this switch or relay may share circuitry and mechanisms ofa ‘DC disconnect.’

FIG. 2A shows a simplified schematic diagram of an embodiment of batterycharge control circuit (200) in accordance with the present invention.Element 202 is a battery module, comprising at least one galvanic cell.The battery module may comprise additional elements as described later.In this embodiment, the battery module is designed to have a highervoltage than that of the connected solar panel, 204. Switch 206,inductor 208, and capacitor 210 comprise a buck converter whereinapplying a periodic gate signal 212 controls the rate of discharge ofbattery 202. Current from the battery module may be applied, to solarpanel 204 through bypass cables 214 and 216 respectively connected tothe positive and negative terminals of the solar panel, to acontrollable load 220 herein generically called an ‘Optimizer.’ In someembodiments an optimizer is a prior-art power circuit that draws powerfrom a bus circuit 222 and supplies the power to a load that is, in someembodiments, an inverter. In some embodiments, the ‘Optimizer’bi-directionally draws and supplies power to bus 222. Some or allcurrent from the battery module or buck circuit (206, 208, 210) may besupplied to the solar panel 204. Some embodiments further compriseswitch 230 controlled by a second gate signal 232. The symbol 218denotes a common voltage that may be used as a reference. In someembodiments, elements 230, 208, 206, and 232 comprise a boost circuit,that boosts bus voltage 222, allowing power to flow from the bus tocharge battery module 202. Elements 240 and 242 are respectivelyresistive voltage dividers that may be included to produce signals 244,a battery voltage indication, and 246, a bus/solar-panel voltageindication. Elements 250 and 252 are respectively current-senseresistors that may be included to produce signals 254 and 256,respectively a battery-charge- and bus-current indication that may beused in a control algorithm. Some alternative embodiments utilizealternative methods or locations to obtain voltage or currentindications as known in the art. Element 260 is an embodiment of‘snubber’ circuit as known in the art. Some embodiments employ no oralternative snubber circuits and locations as known in the art.

FIG. 2B shows an embodiment of a plurality 280 of battery charge controlcircuits that may be stacked while connected to a series-connected arrayof solar panels. Elements 282 and 284 are respectively N−1th and Nthsolar panel in a series connected string. Element 286 is a connectorbetween panels 282 and 284 that further comprises a bypass cable orconnector to a bypass cable to an N−1th circuit 200. Element 288 is asimilar connector to an Nth circuit 200. Each circuit 200 in the stringmay have a different common reference voltage.

FIGS. 3A-F show schematic diagrams of variants of circuit 200. Invariant 300, there is no isolation of the bus voltage on the bus circuit(222) from the solar panel voltage 302. In some such embodiments, thebattery module does not supply power when the photocurrent of the panelis sufficiently low. In some other embodiments, the battery modulesupplies a voltage that is sufficiently low compared to theseries-connected solar cell diode threshold voltage that an acceptablylow current leaks through the solar panel, while providing power for theoptimizer circuit (220) to process. In some embodiments, the Optimizercan supply power to bus 222.

In embodiment 320, a switch 322 controlled by gate signal 324 may beemployed to block current from flowing from the bus to the solar panel.This gate signal may be applied via a level-shifted or isolated signalfrom a microcontroller or logic circuit using the common reference forcircuit 320 or via a second microcontroller or logic circuit that usessubstantially the voltage at 326 as a common reference. In someembodiments that second microcontroller or logic circuit is an elementof a second circuit 320 in a series string.

In embodiment 340, switch 342 and gate signal 344 can block current fromflowing from the bus to the solar panel. Signal 344 can be suppliedwithout voltage isolation by logic or gate-driving circuitry referencedto the common voltage reference of circuit 340.

In embodiment 360, the current sense resistor 362 is located in adifferent position with respect to the bus 222 and Optimizer circuit220. Changing the location of a current sense resistor is known in theart and the locations of these resistors are not intended to belimiting.

Embodiment 380 uses a switch 382 or plurality of switches, e.g., 382 and384 to prevent current from flowing from bus 222 to 302. Someembodiments further comprise a gang between a plurality of switches 386.In some embodiments, this switch is located proximal to or comprises awire-terminal connector. In some embodiments, one or more of theseswitches comprise a ‘DC cut-off switch.’ In some embodiments at leastone switch is actuated. Such a switch may avoid duplication of seriesswitches in the conductive path between a panel and circuit 200.

Some embodiments comprise a DC cut-off switch that may further provide aseries connection of battery modules directly to the input of aninverter. Some such embodiments may have the advantage of reducedconverter losses. Some embodiments alternatively connect circuits 200 inseries.

Embodiment 390 contains an auxiliary circuit that may feed power to thebus 222 from a source other than the battery module, solar panel, orOptimizer circuitry.

FIG. 4 shows a hypothetical array 400 of four circuits, each operatingin different modes that would be typical of a system during daylighthours. A string current flows through conductors along path 402. In someembodiments, some of these conductors comprise cables integrated intothe solar panels. Circuit 420 is operating to charge the battery byclosing an isolation switch, if present, by applying a fixed highpotential 422 to a gate and by further applying a sequence of pulses 424to a switch 230 to effect a voltage boost to apply a charging voltage orcurrent to the battery. Some alternative embodiments comprise a buckconverter, wherein the panel is at a higher voltage than the chargingvoltage of the battery. In some embodiments a pulse sequence 426 isapplied to a second switch 206 to reduce losses in the manner of asynchronous rectifier, known in the art. In some embodiments, thecurrent through inductor 208 is continuous and the gate voltage 426 is aconstant high voltage, leaving the switch 206 closed. The arrows depictcurrent. Solid arrows depict the direction of substantially DC currents.Dashed lines depict pulsating currents. Thicker lines depict greatercurrent. Current 428 drawn from the solar panel 430 is converted tobattery charging current 432. Current 434 comprises the return currentof from the charging circuit. In some embodiments, this current sumswith the current 442 in the bypass cable and the current drawn bycircuit 440 at node 436.

In 440 the Optimizer (220) is drawing power from the panel and thebattery charging and discharging circuit is turned off by applyingoff-state gate signals 448 and 446.

In 460, the battery module is supplying current 462 through a buckconverter circuit to add current 464 to the node 456. The buck converteris controlled by applying an off-state gate voltage 466 to the boostswitch 230 and a pulse train 468 to the buck switch 206. As a result, acurrent 472 flows into the node between panels 450 and 470.

In 480, current is being drawn both into the optimizer and batterycharger circuit.

The magnitude, and in some embodiments direction of the bypass currentextracted from the solar panels may be adjusted in concert with or inreaction to the string current along path 402 such that each solar panelis substantially operating at its maximum power production point. Thedecision to charge a battery, discharge a battery, draw power into anoptimizer, source power from an optimizer, isolate a solar panel, and toexchange power from an auxiliary circuit to or from a battery may bemade in concert to achieve one or more of: a target state of charge forat least one battery module, operation of a solar panel at its maximumoperating point, operation within a temperature envelope, operationwithin a voltage envelope, operating within a current envelope,operating within a power limit, operating within a surge power limit.

FIG. 5 shows an embodiment 500 comprising a plurality of switches 502 ora ganged switch (gang 504), comprising an array of embodiments ofcircuits 200 each having a separately determined gate waveform (510,520, and 530) controlling a buck converter (e.g., 512) to produce acommon current 506 to terminals 508 and 509, which in some embodimentsare DC power input connections to an inverter. In some embodiments aswitch 230 is driven with an on-state gate signal 540 while switch 206is driven with an off-state gate signal 542 such that current is shuntedfrom the battery pack through 230.

In some embodiment the control waveforms (e.g., 510, 520, 530, and 540,542) are jointly adjusted to do one or more of the following: drive abattery toward a desired state of charge, balance the state of charge ofa battery, connect a battery constantly, disconnect a batteryconstantly, discharge a battery, produce a desired current, produce adesired voltage, produce a desired power, produce a desired voltageacross terminals 508 and 509, limit the voltage across terminals 508 and509, limit a battery temperature, limit a converter temperature, limit apeak current, limit an RMS current.

FIG. 6 shows an embodiment 600 of an array of circuits 620, 640, 660,and 680 (each of the circuits 620, 640, 660, and 680 having one or moreof the features of the circuit 200), each operating in modes that may beused in low or no light. A common string current 602 may flow throughthe array of panels. At some times this current may be zero. At sometimes this current may be negative. Current from a connected solar panelmay be blocked by a switch, e.g., 342 with off-state gate signal 604.Circuit 620 is operating with switch 206 turned on by gate signal 622and 230 turned off by gate signal 624, allowing current and power toflow from the battery module to the optimizer circuit (220).

Circuit 640 is operating with the battery disconnected (via gate signal642) so that the battery is not providing power for the optimizer.

Circuit 660 is drawing current 670 from the battery module and operatingwith voltage from the battery module reduced via applying a waveform 662to switch 206. In some embodiments, a conversion from a battery voltageto another voltage applied to an optimizer may be used for one or moreof: keeping within operating limits, maximizing system efficiency,signaling a status to an optimizer stage, maintaining a constant voltageat the optimizer, providing headroom for fast reaction to transients.

Circuit 680 is supplying current 690 to the battery module by drawingpower from the optimizer. In the illustrated embodiment, the voltagefrom the optimizer is being boosted to the battery module, e.g., byapplying switching waveform 686 to 230 and in some embodiments byapplying a switching signal 682 that makes switch 106 function as asynchronous rectifier. In some alternative embodiments, signal 682corresponds to a constant on-state signal and signal 686 corresponds toa constant off-state signal and the voltage output of the optimizer issubstantially applied to charge the battery module. In some alternateembodiments, a buck circuit powered by the optimizer charges the batterymodule.

Some embodiments of circuit array 600 operate at different times indifferent modes. In some embodiments, the mode of each circuit 620, 640,660, 680 is selected and the operating point of that mode may be set toperform one or more of the following: drive a battery toward a desiredstate of charge, operate an optimizer at an efficient power point,operate an optimizer within a desired input voltage/outputvoltage/current envelope, maintain a desired bus voltage at the outputof an optimizer, maintain a voltage or voltage range at the input of aconnected inverter, keep a temperature within a range, keep a currentwithin a range, keep a power within a range. Some embodiments select theoperating mode and operating point based on a measured or inferredcharge state of a battery.

The circuit array 600 in some embodiments is feeding an inverter via aplurality of optimizers. In some embodiments, the inverter is connectedto a power grid. In some embodiments the inverter is not connected to apower grid. In some embodiments, the inverter can operate connected andnot connected to the power grid. In some embodiments, circuit array 600provides for supplying power to a load, the grid, or a combination ofloads and grid in low light or at night.

Some embodiments of optimizers only can draw current from a panel. Insome embodiments, a power from the battery module may be discharged tosupplement the panel current in the string, providing limitedbi-directional current flow to the panel. This may produce an imbalancein the state of charge of battery modules. In some embodiments, thisstate of charge may be re-balanced at a desirable time, e.g., a time ofpeak energy price or demand by selectively drawing down relativelycharged battery modules to rebalance the charge state.

Battery Module

Some embodiments of the present invention further comprise at least oneseries arrangement of galvanic cells, herein called a ‘battery’breakably connected to one terminal of a solar panel. As used herein,the term ‘cell’ may refer to a single galvanic cell, or an arbitraryarrangement of parallel and serial galvanic cells. As used herein,‘connection’ means in electrical communication with, i.e., having aconductive path between both connected items. A plurality ofintermediate conductors may be present between two connected items.These intermediate conductors may be semiconductors or have switchableconductance. As used herein, ‘direct connection’ means connectionsubstantially without intermediate items such as long cables, switches,and additional circuitry, but includes printed circuit board traces andthe like where the function of the intermediate circuitry is primarilyto allow the flow of charge between the directly connected objects. Asused herein ‘breakable connection’ means having electrical circuits thatcan be closed, allowing current to flow, or open, preventing currentfrom flowing, through a mechanical motion of conductors toward, across,or away from each-others' surfaces, typically using a connector as knownin the art of electronics, implying a temporary electrical connection asopposed to a substantially permanent connection such as a solder joint,crimp, single-use press-fit, etc. As used herein, the ‘connector gender’differentiates one or more mating conductor pairs and their supporthousing involved in a breakable connection. As known in the art many butnot all such connections are asymmetrical. As used herein, ‘oppositegendered connector’ or ‘mating connector’ describes the correspondingmating connector of one or more conductor pairs. As used herein,connector pair may comprise an arbitrary arrangement of symmetrical orasymmetrical conductor pairs of either orientation.

In some embodiments the battery is packaged with one or more of abattery management system, charge balancer, breakable connectors,non-volatile memory, flash, EEPROM, printed circuit board, wires,voltage detection and supervisory circuits, current detection circuits,thermal sensor, thermal sensor diode or transistor, thermistor, fuse,resettable fuse, resistor, switch, electronic switch MOSFET, IGBT,solid-state switch into a module, herein called a ‘battery module.’ Somebattery module embodiments further comprise one or more of: a seal, alatch, a mechanical reinforcement, an insulator, a heat spreader, heattransfer grease, an indicator.

As used herein, the ‘battery module connector’ comprises the genderedassembly of individual breakable connections of the battery module. The‘battery module mating connector’ comprises the oppositely genderedconnector to that of the battery module connector.

Battery Adapter

Some embodiments comprise a fixture, herein called a ‘battery adapter’which may allow a plurality of battery modules to be combined with atleast one substantially common voltage. Some arrangements aresubstantially parallel. Some arrangements are switched so that onemodule is utilized at a time. Some alternative arrangements haveseparate charge-control circuitry. The advantage of this arrangement mayinclude extended capacity, lower charging or discharging battery stress,and higher discharge current. In some embodiments, the battery gangcomprises circuitry to facilitate a microcontroller to communicateindependently with each connected battery module. This communication maybe digital, analog or both. In some embodiments, the battery gangadaptor comprises one or more battery module mating connectors. In someembodiments, the battery gang further comprises least one battery moduleconnector. In some embodiments the battery adaptor may comprise abattery module connector having a different physical or electricalarrangement. In some embodiments, a battery module adapter may furthercomprise circuitry to enhance the operation of the hybrid inverter ofthe present invention. Some such enhancements may comprise inter-modulestate-of-charge balancing, charge control, adaptation to new designrevisions or vendor requirements, etc. Some embodiments further compriseone or more of: a seal, a latch, a mechanical reinforcement, aninsulator, an indicator.

The assembly of one or more battery modules into a battery adapter isherein called a battery module gang. It is intended that the batterymodule gang be an enhancement to a battery module and for each referenceherein to a connection or operation on a battery module further impliesan alternative connection to a battery module gang. In some embodiments,one or more battery module gangs may be connected to a second batterymodule adapter. Such recursive arrangements of battery modules andbattery module gangs are also herein an implicit alternative to abattery module.

Some embodiments comprise more than one battery module or battery modulegang, each breakably connected to a conductor in electricalcommunication with one terminal of a different solar panel in a seriesstring.

In some embodiments, one terminal of at least one and preferably eachsolar panel in a string has a battery connected via a conductor directlyor through a charge-block switch to one terminal of a battery. In someembodiments, the charge-block switch may block excessive charge currentfrom flowing in a battery fault or over-discharge event. In someembodiments, the charge-block switch is integrated into a batterymodule.

In some embodiments, the charge-block switch default state is off. Insome embodiments, this switch state prevents battery voltages from beingpresent at terminals when the battery module is disconnected. In someembodiments, this default state is set via a pull-down resistor on aswitch gate.

In some other embodiments, the charge-block switch default state is on.In some embodiments, this default state is set via a pull-up resistor ona switch gate to a battery voltage on in the battery module.

Some embodiments comprise a discharge-blocking switch.

Some battery module embodiments comprise a plurality of series-connectedcells, each further comprising a parallel load and switch such thatcurrent in the string of cells may be shunted away from an individualcell. In some embodiments, a supervisory circuit measuring the voltageacross a cell may actuate the parallel load switch when it detects avoltage related to a substantially charged condition. In someembodiments, a microcontroller may sense the cell voltage via one ormore of an A/D converter, resistive voltage divider, analog switch,voltage reference. In some embodiments, the voltage threshold isadjusted for measured battery module temperature. In some embodiments, amicrocontroller may actuate a parallel load switch that shunts currentfrom the cell through a load. In some embodiments, the shunt switch isoperated in a binary on-off sense. In some embodiments, the switch isactuated as a variable conductance. In some embodiments, a supervisorymicrocontroller may communicate an end-of-charge signal to a chargecontroller or change an internal charge-control programming state inresponse to a measured voltage or current.

In some embodiments of the present invention a microcontroller orsupervisory circuit changes its charging state upon detection of an‘end-of-fast-charge’ trigger that occurs when a cell within a batterymodule reaches its end-of-charge voltage. In some embodiments the changeis from a ‘fast-charge’ state, e.g., charging at 0.1-3 C as known in theart, with or without module voltage and temperature feedback control, toa ‘slow-charge’ state, e.g., charging at a lower current or according toa different algorithm. In some embodiments the slow-charging current isless than or equal to the bypass current of the parallel shunt so that acell within a battery module cannot be overcharged. In some embodiments,the end-of-fast-charge trigger is an abrupt change in voltage or currentassociated with the actuation of a parallel load. In some embodiments,this change is detected via analog to digital (AD) sampling on amicrocontroller or a circuit that is sensitive to a relatively rapidchange in the voltage, current, or impedance of the battery module asknown in the art, e.g., an AC-coupled circuit to a comparator, etc.

Isolated Sensing of Cell State

Used herein a ‘deprecated state’ is a state of charging or dischargingthat could lead to damage of a cell, such as an over-temperature,over-voltage or over-current on charge, or an under-voltage orover-current on discharge. In some embodiments a deprecated-stateindication is provided by a supervisory circuit, typically via a one ormore digital signal lines, each, possibly containing a pull-up orpull-down resistor to establish a quiescent state. If each supervisorcircuit is referenced to a cell potential, an isolated means of sensinga deprecated state on a common-module signal line may be needed. In someembodiments, each supervisor's indication is connected capacitively tothe same signal that is detectably disturbed from quiescence by a changeto a deprecated state of any cell. In some embodiments, the supervisorindication is connected to an electronic switch that changes theimpedance of the common signal line, e.g., by electrically connecting aseries capacitor on the line to an AC ground, e.g., the positive ornegative battery voltage. In such an arrangement, a change to adeprecated state may be detected by an microcontroller or other circuitby momentarily driving the common line from quiescence and measuring howlong it takes for the voltage or digital state on the line to return toquiescence after removing the driving, e.g., by tri-stating abi-directional pin. This delay may be measured periodically or oncommand while the battery module is being charged. An advantage of thetime-delay measurement may be a reduced sensitivity to noise spikes or arelaxation in the prioritization of sampling a pin, since themeasurement can be repeated, where a single transition event may bemissed or incorrectly detected, e.g., because of noise or latency.

In an embodiment, the nominal return-to-quiescence delay may be detectedwhen it is separately known or inferred that all cells are not in adeprecated state. This may allow differences in parasitic capacitance ofdifferent modules and module gang arrangements to be compensated.

In some embodiments, calibration and information parameters associatedwith a battery module may be stored in non-volatile memory in a batterymodule, including one or more of: battery type, threshold over- andunder-voltages and over-currents, capacity, serial number, temperaturecoefficients, charge algorithm parameters, date of manufacturing,manufacturer, lot number, location of manufacturing, etc. In someembodiments, this memory may be accessed by a serial communication meansas known in the art, preferably one that provides for communicating withdaisy-chained or bussed devices, e.g., SPI, I2C, UNIO, and other schemesknown in the art. Some embodiments further allow data to be written tonon-volatile memory in a battery module. Such data may include one ormore of: cycle count, charge-discharge history, data logs, measuredcharge/discharge capacity, measurements, voltage, current, temperature,resistance, faults, and run-time parameters of use in optimizingcharging/discharging algorithms. In some embodiments, usage data storedon a battery cell may be used as part of a recycling/reuse program tobin modules, diagnose premature failures or degradation, identifysupply-chain problems and to refine charge-control algorithms.

In some embodiments, a visual machine-scannable code, e.g., a bar code,QR code, etc. bears static module information in a non-contact scannableexterior location.

In some embodiments of the present invention a microcontroller orsupervisory circuit changes its discharging state upon detection of an‘end-of-discharge’ trigger associated with a cell within a batterymodule reaching its end-of-discharge voltage. Some embodiments of thepresent invention comprise a supervisory circuit measuring the voltageacross each cell in a string that sets or clears a digital output whenthe cell voltage drops below a threshold.

Swapping Battery Modules

In some embodiments of the present invention, a technician or end usermay periodically, on detection of a fault, or on detection of anon-ideal battery arrangement, disconnect a battery module and plug in abattery module. In some embodiments, a battery module position may beswapped so that a battery is connected to a different panel in a string.In some embodiments, a new battery module may be inserted. Someembodiments support a plurality of battery types, voltages, capacities,maximum currents and ages/cycle counts by separately tailoring chargeand discharge parameters per battery module.

The swapping of battery modules may be software optimized and guidedstep by step using an app or software.

In some embodiments, a battery module having reduced or enhanced chargecapacity may be inserted, for example to tailor the battery capacity toexcess or deficit power production of a panel in a string.

FIG. 7A shows a front view 700 of a battery module according to anembodiment of the present invention. Elements 702 are an array ofseries-connected rechargeable batteries. Element 704 is a battery chargemanagement circuit board with individual connections 706 to thejunctions between batteries (708). Elements 710 and 712 arebi-directional power connections. Element 712 is a set of auxiliaryconnections to the battery charger controller of the power module (106)that communicate one or more of: end of charge, end of discharge, celltype, temperature, charge profile, charge history, state of charge,serial number, date of manufacturing, charge/discharge limits, cellchemistry.

FIG. 7B shows a side view 760 of a battery module embodiment. Keepingcells in a single layer may assist in maintaining uniformity in celltemperature, minimize cell overtemperature, and foster improved firesafety of more densely-arrayed cells.

FIG. 7C shows a back view 780 of a battery module embodiment.

FIG. 8 shows a schematic diagram of a battery charge management circuit800 according to an embodiment of the present invention, comprising anarray of sub-circuits 802, each having a connection across a battery inthe series array 804. Parts and component values in parentheses areillustrative and are not intended to be limiting. In this embodiment, astandard battery management integrated circuit 806 senses the batteryvoltage with high precision. When 806 detects the cell voltage hasreached a substantially charged-state level, the circuit drives pin CO(808) low, turning on switch 810 and shunting charge and battery currentthrough ballast resistor 812. When 806 detects the cell voltage hasreached a substantially discharged-state level, it drives pin DO (814)low, turning on switch 816, which applies an AC-ground via capacitor 818to the common undervoltage sense circuit 820. In this embodiment, thissignal is multiplexed with a chip-select signal for a memory device 822.A pull-up resistor 821 may combine with one or more instances ofcapacitor 818 when one or more cells are discharged to increase the risetime of signal 820 from a low state. Such a change in time delay may beused by a microcontroller or other circuit to detect end of discharge.

A charge-enable signal 824 may be applied to switch 826 to allow thebattery module to charge, e.g., to stop blocking reverse current. Someembodiments further comprise an over-discharge-current limiter, providedfor example by a supervisory circuit such as a an AP9101C integratedcircuit in concert with a switch such as a MOSFET as known in the art.Only one such circuit is required per module since all currents are inseries. Some such circuits further comprise a transient voltageprotection device to prevent damage to the switch from inductive voltagespikes. Some embodiments use one of the existing circuits 806 to performthis function. Some embodiments use an extra supervisory circuit havingat least one different voltage threshold setting from that of 806. Somecircuit embodiments further comprise a positive temperature coefficientresettable fuse. Some circuit embodiments further comprise aconventional fuse. Some circuit embodiments further comprise a circuitbreaker.

Elements 828 and 830 are respectively the positive and negative outputterminals of the battery module.

External Switch Actuator

Motorized and actuated circuit breakers and switches are known in theart. Such prior-art breakers may cost a premium over standard commodityswitches and breakers. An element of the present invention is anexternal switch actuator that mimics the action of fingers on eitherside of the switch lever of a commodity breaker or switch, herein calledactuator ‘fingers.’ Fingers according to the present invention maycomprise an object having an edge substantially perpendicular to themotion of a switch lever on either side of a switch lever. Some fingerembodiments comprise a slot or hole in a sheet-metal or plastic bar.Various embodiments of an external switch actuator allow manual overridein one (on or off), two, or no positions, or only on emergency override.In some embodiments, the mechanism of denying override is to maintainthe actuator fingers in a position that prevents the switch state frombeing manually changed, but allows the normal function of the switch,e.g., allows a circuit breaker switch lever to flip to its trippedposition, but not be reset manually. In such a case an actuator fingermay be actuated to a position that flips the switch, then backed to anintermediate position. In some alternate embodiments, the breaker switchis held firmly in the ‘on’ position and the internal relay mechanismthat prevents re-closing is relied upon for proper breaker action, withthe disadvantage that the breaker-lever position stops properlyindicating the tripped state. For standard switches or for breakers setto the off position without manual override, the fingers may be actuatedwithout the backing operation. For switches without manual lockout, thefingers may be spaced and backed into a position following switchingthat allows the switch lever to be flipped in either direction withoutinterference. Some embodiments of the present invention allow anemergency override by lifting the fingers away from the switch lever.Some embodiments of the present invention comprise a fixed or removablemechanical component linked or unlinked to the fingers to prohibitmanual actuation. Some embodiments of the present invention allowprohibition functions of an actuator to be set in the field byinstalling an inhibitor apparatus of the desired functionality.

Some embodiments further comprise a housing that provides reactionforces to allow fingers to actuate switches. Such forces may berelatively high for certain switches, such as service disconnects. Somesuch housings compromise one or a plurality of fixed magnets, such asrare-earth, AlNiCo, etc., that hold the switch housing to the steelsurface of a switch panel. Some embodiments employ a plurality ofmagnets. Some such magnets have a component of offset in the directionof switch actuation between 10 mm and 200 mm and preferably in the range50-120 mm. Some such magnets have a total attractive force to a paintedsteel panel of 5-100 N and preferably in the range 20-90 N for a servicedisconnect switch and 5-50 N per breaker pole. Some housings provide amechanical means to assist with disassembly from the panel, such as acam, a screw, a lever, etc. that overcomes the magnetic attraction tothe panel. Some such housings comprise one or a plurality of mountingtabs that slide into the slot between a breaker or switch and its slotin a switch housing. In embodiments these tabs are disposed on the sidesof the slots perpendicular to the switch-lever motion, thin enough tofit into the narrow slots, and strong enough to resist the switchactuation force. Some embodiments of finger comprise anti-corrosionplated or painted steel of 0.1-2 mm thickness and widths thatsubstantially match the switch height, e.g. 2-50 mm that extends 0.1-5mm into the slot. In some embodiments these mounting tabs furthercomprise a curvature or fold that resists motion of the tab from theslot. In some embodiments, one or more of these mounting tabs is springor flexure loaded and installation into the slot may involve manuallyovercoming flexure forces over a bump, then continuing to a flexure orspring-loaded detent. Installation in some embodiments may involvepressing a button that compresses a spring or provides temporary flexureto allow insertion. Some embodiments provide a mechanical lockingmechanism after insertion into the slot that positively locks the tabsto the slot. Such a mechanism may comprise a screw, lever, plasticallydeformed, or geometrically or topologically changed assembly of a partof parts. Some embodiments of mounting tabs are disposed to be factoryor field installed to accommodate different families of panels andbreakers. Embodiments provide for stable mounting without modificationof the existing panel.

Some housing embodiments further comprise a connector to one or more of:an external controller, battery, motor, solenoid, ratchet, gear train,worm gear, lead screw, finger guide, limit switch, detent, indicator,pushbutton, resistor, capacitor, transistor, MOSFET, half-bridge, fullbridge, gate driver, inductor, voltage regulator, charge controller,microcontroller, wireless module, antenna, coaxial cable. As usedherein, a wireless module is any uni- or bi-directional communicationslink that does not require a wired connection, e.g., Bluetooth, BLE,zigbee, wifi, cellular, near-field, RFID, etc.

Some embodiments of actuators further comprise a means of passing atleast one conductor between the interior and exterior of a panel hereincalled a ‘panel feedthrough.’ In some embodiments, a panel feedthroughis mounted in an unused breaker or switch position. In some embodimentsthe panel feedthrough is installed in part by inserting a feedthroughcover containing at least one conductor in a hole in the panel, such asa breaker knock-out. In some embodiments the feedthrough cover snapsover the sheet metal of the panel and is mechanically held in place byone or more of a pawl, mechanical flexure, tab, tooth, etc., as known inthe art.

Some embodiments of actuators further comprise one or more means ofpassing a radio frequency signal from the interior of a panel to theexterior, herein called an ‘RF feedthrough.’ In some embodiments this RFfeedthrough comprises passing one or more of: a coaxial cable, antenna,wireless module, conductor, mount, through a hole in the panelenclosure, e.g., a knockout hole. In some embodiments, the RFfeedthrough is held in place by a nut in a manner similar to commonknock-out connectors. In some embodiments, the feedthrough is held inplace by a pawl, mechanical flexure, tab, tooth, thread, etc. as knownin the art. In some embodiments the feedthrough further comprises awater-tight or resistant seal comprising one or more of: a gasket,o-ring, weather stripping, gel, grease, glue. In some embodiments, athin slot antenna is connected at an open seam, slot-like gap in thepanel, knock-out, interface between two sheet metal surfaces, interfacebetween a panel door and housing, opening in a panel as known in theart. In some embodiments, the mechanical connection is made by one ormore of adhesion, glue, magnetic force, a mechanical fastener, friction,mechanical preload, e.g., between two metal pieces, such as an enclosureand panel. In some embodiments, the RF feedthrough is a thin slotantenna positioned between a panel door and panel. In some suchembodiments, the slot antenna assembly is thin enough not to interferewith the door closure. In some embodiments, an RF cable passes to anantenna in the space between a panel door and panel. In someembodiments, an RF cable passes through the space between a panelenclosure and front panel.

Some embodiments of actuators further comprise a sensor, sensitive toone or more of: a voltage, a voltage difference, an AC voltage, an ACvoltage difference, a current, an induced magnetic field, anelectrostatic field, an electromagnetic field, temperature. Someembodiments of actuators comprise a capacitive connection to one or moreAC circuits.

Some embodiments of sensor capacitors comprise an electrical conductorconnected to a conductive sensor surface near a bus bar or wire. Someembodiments of sensor surfaces further comprise an insulating spacer. Insome embodiments the insulator has a dielectric constant substantiallygreater than 1. Some embodiments of insulators may be compliant. Someconductive or insulative sensor surfaces further comprise an adhesivedisposed to hold the sensor in place.

Some embodiments of sensors comprise a magnet and one or more of aninsulator, conductor, resistor, capacitor, resistive divider. In someembodiments, a sensor is magnetically connected to a ferromagnetic pieceof hardware, e.g., screw, nut, bolt, etc., in electrical communicationwith an AC or DC circuit.

In some embodiments a microcontroller in the actuator takes ameasurement using a sensor. In some embodiments, the measurement is oneor more of: voltage, current, frequency, AC rms voltage, AC rms current,phase, zero-voltage crossing time. In some embodiments, amicrocontroller may be used to compare a measurement with aspecification. In some embodiments, this comparison may be used all orin part to determine when to actuate a disconnection or connection. Insome embodiments, results of this comparison may be reported to anexternal system or microcontroller, e.g., via a wired or wirelesscommunication channel.

Actuator and Feedback

Some switch actuators according to embodiments of the present inventioncomprise an electric motor such as a DC motor, brushless DC motor, ACmotor, variable reluctance motor, synchronous motor, universal motor,stepper motor, etc. coupled to a linear or rotary translator that movesthe actuator fingers. Because of the high peak actuation forcesrequired, e.g., 30-90 N at the end of a typical service disconnectswitch lever, a force amplification stage or sequence offorce-amplification stages may be employed including one or more ofplanetary gear reduction stage, a standard gear reduction stage, a wormgear, a lead screw, a lever. Some actuator stages further compriseposition feedback via one or more of: a limit switch, a linearpotentiometer, a rotary potentiometer, pulse counting, an encoder, anopto-interrupter, a hall-effect device. Some actuator stages providediscrete position indications, comprising one or more of end-of-travel,home, operate, center, and constant increment. Some actuator stagesdetect position via sensing motor current. Some actuator stages provideposition feedback for discrete positions via one or more mechanicaldetent which produces a signature motor current waveform near the detentposition. Using a current-feedback approach may have the advantage ofmimicking force feedback, which may provide additional confirmation ofactuation to the actuator by comparing the current history during anactuation to an expected profile. Because the actuation of breakers maybe typically direction dependent, the current or force history onactuation can be used to detect the orientation of the breaker leverwith respect to the actuator.

In some embodiments, the current or force history may be used to detectwhen a breaker is in its tripped position. In some embodiments, abreaker state may be tested without a complete actuation by sensing thelever position and resistance to motion via driving the fingers partway,but not far enough to switch the lever. In some embodiments, thissensing may be used provide remote notice of a breaker tripping.

Some alternative actuator embodiments employ a solenoid and ratchetmechanism.

Non-volatile Actuator Settings

Some embodiments of the present invention allow prohibition functions ofan actuator to be set via non-volatile electrical settings. Someembodiments of actuator controllers have additional control settingscomprising one or more of: dead-man's switch or watch-dog-timeroperation in which failure to receive a signal in a programmable timewill result in a programmable action, programmable time delays,programmable retry intervals for reclosing breakers, programmableinterlocking wherein at least one actuator state is or a command to moveto an actuator state is enabled or disabled by another condition, suchas the state of a second actuator or switch, a programmable time-of-dayswitch timer, a programmable circuit priority, a descriptive name forthe breaker, a serial number, a panel-slot number, an electronicaddress, relay or circuit ampacity, security certificate, encryptioncode, authorization table, switch position locations, etc.

An objective of the present invention is to allow common actuatorhardware to mount and actuate properly with minimal or no customizationfor different switch or panel hardware.

To accommodate different types of switches and circuit breakers, whichmay generally have different actuation force requirements, a step duringinstallation may comprise actuating a switch in one or more directionswhile saving current or force measurement data and processing themeasurement history into motion parameters saved in non-volatile memory.In some embodiments, these motion parameters may be used to detect thestate of a switch or breaker non-intrusively. In some embodiments, thesemotion parameters may be used to reduce stress on an actuator motor orits gear mechanism.

The height of a switch or circuit breaker over a panel may vary from onemanufacturer to another. In some embodiments installation may follow oneor more of the following steps:

1) Place a magnetically held mounting and reaction plate onto a panelsurface in a position where tabs slide into the gap between the paneland a switch or breaker.

2) Connect an actuator mechanism and housing to the reaction plate via amechanical fastener as known in the art, wherein the fastener andmechanical design of the reaction plate and housing permit a stand-offheight adjustment.

In some alternative embodiments, the mounting and reaction plate may becombined with a housing when placed on a panel and the actuator heightadjusted by pressing on the housing while at least one mounting featureratchets down another mounting feature in a manner similar to that of a‘zip tie.’ In some embodiments, the actuator height is adjusted byturning a screw, bolt, cam, or other mechanism known in the art.

Ganged Actuators

Some housing embodiments comprise a plurality of mounting tabs andindividually controlled actuators such that a plurality of actuators canbe installed at substantially the same time. Some alternative housingsfor ganged actuators comprise a gang housing into which separatelyhoused actuator assemblies are inserted. Some embodiments of a gangedhousing comprise a high-level controller having a wired or wireless orpanel-based control interface, further comprising one or more of a wiredcommunications bus, a battery, a charge controller, an AC connection, acommunication bus, a digital hand-shaking line, a visual indicator, acapacitor, a transient voltage suppressor, a MOV, a temperature sensor.

In some embodiments, a ganged housing is first installed magneticallyonto a panel. In some embodiments, mounting tabs are disposed on theganged housing. In some embodiments a digital communication connectionis established with a microcontroller in the ganged housing. In someembodiments, an actuator assembly is installed into the ganged housing,making electrical contact with a wired connection to themicrocontroller. In some embodiments, the microcontroller detects thepresence of a new actuator on its bus by measurement, e.g., of a currentor analog or digital voltage, or polling of a non-configured address.Upon detecting the new actuator, the microcontroller assigns theactuator a non-volatile address. In some embodiments, themicrocontroller may automatically detect the slot location of theactuator and update this information in the actuator non-volatilememory. The microcontroller sets non-volatile parameters of the switchvia instructions from an external digital wireless or wired connectionto a device such as a cell-phone or computer running a configurationapplication.

In some embodiments, power is drawn from an AC line, e.g., a separatelyinstalled breaker on a panel. In some embodiments this power is used tomaintain a state of charge of a battery. In some embodiments, this poweris used to actuate a switch motor. In some embodiments, the batterypower is used to actuate switches and supply uninterrupted power to acontroller. In some embodiments, AC power is supplied from a circuit inthe panel that has uninterruptable or briefly interruptible backuppower.

Automatic Transfer Switch

A switch actuator according to the present invention, on a panel servicedisconnect relay or switch may be a component of an automatic transferswitch. When it is time to actuate the transfer switch, this switch mayreceive a secure wireless command from an external controller to openthe service switch. The actuator then performs the opening procedure andwhen the switch opening is confirmed by position or impedancemeasurements, the switch actuator transmits a secure acknowledgement orresponds to a poll with an indication that the switch is open. Then theexternal controller can engage a secondary power source. In someembodiments the power source is an inverter.

In some embodiments, a controller associated with the switch actuatorcan sense the voltage and frequency of an AC power line. In someembodiments the switch actuator can sense the current waveform of an ACpower line. In some embodiments, the switch actuator can further sensecurrent or voltage or both in a neutral line. In some embodiments theswitch actuator can sense the voltage on the grid side of the switch. Insome embodiments the switch actuator can sense the voltage on thenon-grid side of the switch. This sensing can be performed by one ormore of: electrostatic, inductive, magnetic, direct coupling, couplingthrough a resistor, capacitor, or inductor. A controller may beconfigured to monitor the grid-side AC waveform. It may report theseparameters on polling or may pro-actively transmit commands or alarms toexternal devices when it detects an excursion past one or more limits.In some embodiments, the reactive power drawn or delivered to the gridmay be quantified and subject to polling or proactive commands.

It may be desirable to detect when the grid has been restored to normalafter a service switch is opened. However, the inverter circuitry thatnormally senses the grid may, in that state, be disconnected from thegrid and unable to sense the AC waveform. In some embodiments, theinverter may periodically stop producing power, command the transferswitch to close, assess the status of the grid, and take appropriateaction. This may have the disadvantage of producing periodic blackouts.To avoid these blackouts, some embodiments incorporate the serviceswitch and grid-side sensing circuitry in the inverter housing. Someembodiments, comprise a wired sensing line from the inverter housing toan external grid-connected circuit. Some embodiments comprise a wiredsensing line to a secondary housing. In some embodiments, the secondaryhousing further comprises a service disconnect switch. Some embodimentscomprise a wireless data connection to an external grid-connectedsensing and reporting circuit.

In some embodiments, a controller within the hybrid inverter systemcommunicates with a smart meter through a wireless, wired, or digitalhand-shaking channel. Over this channel, it may read the grid status. Insome embodiments, it may read additional information including one ormore of: AC voltage, AC current, AC phase, AC frequency, grid operatordirectives. In some embodiments this microcontroller may translate andrelay information from the smart meter to a remote microcontroller. Inembodiments, this controller, herein called a ‘communications relaycontroller’ is physically close to a smart meter for reliablecommunications. In some embodiments, the ‘communications relaycontroller’ is housed with a switch actuator. In some embodiments thisswitch actuator actuates a service switch directly or through a wiredcommunication link. In some embodiments, this ‘communications relaycontroller’ is located within an inverter housing. In some embodiments,the ‘communications relay controller’ provides grid-status informationneeded to decide when to reconnect the service switch.

Some embodiments of systems having sufficiently low sensing latency mayuse instantaneous measurements of the grid to synchronize the inverterback to the grid when the grid returns. This may be achieved by slewinga clock frequency so that the waveform phase mismatch is nulled. Thisslewing may be performed by adjusting an RC-timer calibrationprogrammatically. This adjustment may be gradual through a control loopsuch as a PID or other feedback loop known in the art. The frequencyadjustment may further comprise a periodic dither to achieve highfrequency resolution. This frequency adjustment control loop may runcontinuously while connected to the grid. In some embodiments, theinstant of zero-crossing of the grid voltage is compared to a digitaltimer as a high-resolution relative-phase measurement. In someembodiments, A/D conversions, with or without interpolation orcross-correlation is used to calculate a high-resolution relative phasemeasurement. In some embodiments, both synchronization techniques areemployed as cross-checks. It may be advantageous to suppress falserelative-phase measurements arising from momentary voltage or currentspike, noise, inverter-currents and the like. Some embodiments employtrigger gating over windowed intervals to ignore zero crossings fromoutlying transients. Some embodiments employ limits on slew-rates of atiming control system so individual outlying zero crossings have anegligible overall effect.

In some embodiments the high-resolution phase information is transmittedover a wireless, time-synchronous signal or data packet. In someembodiments, this data packet comprises one or more of: a packet latencymeasurement, an rms, peak, or instantaneous voltage measurement. In someembodiments this wireless signal is detected at a microcontroller withlow latency. In some embodiments the microcontroller controls the phaseof the inverter output. In some embodiments, the transmitted latency isused to correct communication delays when calculating or driving theinverter-generated-waveform phase.

Disconnect from Grid Procedure

As used herein, ‘load side’ is the circuit disconnected from service ina service disconnect switch and ‘grid side’ is the circuit maintaining aconnection to a power grid or other substantial power source in aservice disconnect switch.

As used herein ‘pre-disconnection programs and procedures’ refer to oneor more of: starting or changing the state of a computer program,sending an electronic message, opening a smart load switch, opening asmart breaker, opening an actuated switch, sequentially de-energizingcircuits, deenergizing circuits according to a priority based on theavailable solar and battery power.

In some embodiments of the present invention the inverter system willautomatically disconnect from the grid if it detects that the grid isoutside set parameters, herein called a ‘bad grid state.’

In some embodiments, the disconnection procedure follows thesequence: 1) one or more of: a communications relay controller detects abad grid state and relays that information remotely to the inverter; amicrocontroller senses a bad grid state and relays that informationremotely to the inverter; a microcontroller housed in the inverterdetects a bad grid state; 2) pre-disconnection programs and proceduresare initiated; 3) an autotransformer circuit is connected to the loadside circuit; 4) the inverter switches to a disconnection-operatingmode; 5) an actuator opens the service switch; 6) the inverter switchesto a voltage-feedback or combination voltage and current feedbackoperating mode.

In some embodiments the ordering of 2 and 3 are swapped. In someembodiments the disconnection-operating mode comprises turning off itsoutput. In some embodiments the disconnection operating mode comprisestransitioning from current-feedback to voltage feedback abruptly orgradually. It may be advantageous to connect the autotransformer beforeopening the service disconnect to mitigate overvoltages and imbalancecurrent running through a grounding circuit.

Return to Grid Procedure

As used herein ‘post-reconnection programs and procedures’ refer to oneor more of: starting or changing the state of a computer program,sending an electronic message, closing a smart load switch, closing asmart breaker, closing an actuated switch, sequentially energizingcircuits.

In some embodiments the reconnection of a system to the grid follows thesequence: 1) one or more of: a communications relay controller detects agood grid state and relays that information to the inverter; amicrocontroller senses a good grid state and relays that informationremotely to the inverter; a microcontroller housed in the inverterdetects a good grid state; 2) the inverter powers down its output,producing a momentary ‘black out.’ 3) an actuator closes the serviceswitch, restoring power 4) an actuator switch removes an autotransformerfrom the ac circuit lines. In some embodiments having a split-phaseinverter, there is no need for an autotransformer and step 4 is skipped.5) ‘Post-reconnection procedures and programs’ are initiated.

In some embodiments, the reconnection sequence is 1) the invertersynchronizes its phase and, in some embodiments, voltage based on one ormore of: high-time-resolution measurements of the AC grid, an externallygenerated wireless synchronization signal, a wired synchronizationsignal, a time synchronized wireless data packet; 2) an actuator closesthe service switch; if present, 3) an actuator removes anautotransformer from the ac circuit lines.

Inverter and Balancer Connections

As used herein, ‘power module’ comprises the packaged electronicsassociated with one or more of: a Balancer optimizer, an inverter, abattery module, a capacitor module, a charge controller. As used herein,a ‘wire-terminal connector’ comprises one or more mechanical andelectrical components by which one or more wires are separatelybreakably connected to a power module.

In some embodiments of the present invention, a Balancer optimizer stageis employed wherein one or more bypass cables connect between theBalancer unit and the normal string connections each via a ‘Y’ or ‘T’connector inserted between the normal solar panel power connectors in astring. In some embodiments of the present invention these bypass cablesare bundled and routed to an enclosure. In some embodiments the bundlefurther comprises the main string cables at the voltage extrema of oneor more strings.

In some embodiments, each bypass cable is connected to a terminal thatis mechanically coupled to a common insulator and electrically coupledto a breakable connector terminal. In some embodiments, the electricalconnection is mechanical, e.g., via a spring, screw, lever, crimp asknown in the art. In some embodiments the electrical connection is via aweld, solder, conductive glue joint. Some embodiments comprise aterminal block as known in the art. In some embodiments, this terminalblock may further provide one or more of AC connections, interlockconnections, digital signaling connections, analog signalingconnections, handshaking connections, switch state indicators,connections to indicators, such as LEDs, a plurality of connectiongeometries or connectors, a circuit having a physical offset that delaysor advances its time of connection relative to another circuit, acircuit having a resistive lead-in that may reduce in-rush currents, avoltage surge suppression circuit such as a transient voltagesuppressor, avalanche device, metal oxide varistor, and the like, aflexible conductor element, mounting hardware and accommodation, amagnet, a ferromagnetic material, an articulated mount, a spring, amechanical contact to a cam actuator, a mechanical contact to a leveractuator, a motor, a solenoid, an arc-suppression insulator, aconductive bus bar, a plurality of spring-loaded electrodes.

In some embodiments, a plurality of DC connections may be substantiallysimultaneously opened, by a translational or rotational motion. In someembodiments, this motion may actuate a breakable connection to the powermodule. In some embodiments, the terminal block or wire connection andbreakable connection move together. In some embodiments, the motion ofthe breakable connection and wire connection are isolated through aflexible conductor. Some embodiments maintain a closed connector stateby one or more of: magnetic force, mechanical force e.g., against alever, ratchet, cam, latch, friction force, gravity force. Someembodiments comprise a mechanical preload that rapidly opens theconnector a distance substantial enough to extinguish an electrical arc.This mechanical preload may comprise one or more of a spring, torsionalspring, leaf spring, coil spring, flexible element, mass. Someembodiments further comprise an arc-suppression element that deploys onthe opening of the connector. This element may be an insulator,resistor, conductor, or semiconductor.

The wire-terminal connector assembly may comprise a position in whichone or more bypass and string wires are short-circuited by a conductor.In some embodiments, this short-circuiting conductor comprises a secondbreakable connection to a mating connector with internal or externalconductors comprising the short circuitry. In some embodiments, all or apart of the wire-terminal assembly may move to a position when aplurality of conductors come into contact with a plurality ofelectrically conductive points having a common conduction path. In someembodiments, these points are electrical contacts having a spring orflexible loading. In some embodiments, these points are the surface of aconductive bus bar. In some embodiments, the mating contacts in thewire-terminal assembly have a spring or flexible loading. In someembodiments, the closure of the short circuits effects avoltage-suppression function or ‘rapid shutdown.’ In some embodiments,the physical arrangement of conductors staggers the short-circuit time.In some embodiments, at least one resistive element makes first contactto reduce switching transients.

In some embodiments, the redundancy of connections from the bypasscables confers additional surety against the presence of unwantedvoltages via redundancy. E.g., if a connection fails between the panelsor anywhere in the circuit, the redundant short-circuit connectionslimit the maximum possible voltage during shut-down substantially to asingle-panel open-circuit voltage.

In some embodiments, the actuation of the wire-terminal connection iscontrolled via one or more of: a rotary knob, a linear knob, a pluralityof knobs, a cam, a lever, a mechanical linkage, a motor, a solenoid, acontrol circuit. In some embodiments, a single knob may have a separate‘connect,’ ‘disconnect,’ and ‘shut-down’ position. In some embodimentsthese positions correspond to mechanical detents in a cam, lever, orlinkage. In some embodiments, a switch knob rotates in only onedirection. In some embodiments, a mechanical contact does one or moreof: translate along a ramp, directly or indirectly increase the strainenergy of a spring or flexure, drop down an abrupt change, e.g., a toothor ratchet in a rotary or linear cog mechanism, releasing strain energy,drop into a detent position.

In some embodiments, circuitry in the power module can sense or becommunicated information about the actuation of the wire-terminal arraybefore a power circuit opens or closes via one or more of: a separatelydisposed circuit, a magnetic switch, a mechanical coupling to a switch,or other position-sensing or communications circuit known in the art. Insome embodiments, the circuitry uses this advance notice to change anoperating mode. In some embodiments, the circuitry does one or more of:turns off a power switching circuit, stops battery charging, stopsbattery discharging, stops drawing bypass current from a panel, stopssupplying AC current, closes a switch to draw maximum current from apanel.

Some embodiments of wire-terminal connectors have one or more wireterminals whose connections may be broken separately from others. Somesuch connections may be AC connections, switch-position indicatorconnections, signaling connections, uninterruptable power connections,sensing connections.

Some embodiments of wire-terminal connections have one or more wireterminals whose connections are broken by removing the power module fromthe mating connector.

Some embodiments of hardware associated with the wire-terminal connectoror its enclosing housing comprise one or more latch to secure aconnector. Some embodiments of such a latch further comprise amechanical or electrical position indicator. In some embodiments, suchan indicator is used as a safety interlock. In some embodiments such anindicator switches a mode of operation of the power module.

Thermal Management

Some embodiments of power modules according to the present inventioncomprise a design architecture herein called a ‘cooling fin body,’wherein the housing is one or more bent sheet or thin extrusion of metalhaving a slender aspect such that thermal diffusion length from a heatsource to an exterior surface through the interior is substantiallydominated by the component dimensions and where both sides of thecooling fin body transfer a substantial quantity of heat to the air orheat-transfer fluid. Cooling fin body designs do not overly restrict orimpede forced or natural convective heat transfer.

Cooling fin bodies in accordance with embodiments of the presentinvention are substantially in intimate thermal contact with significantheat producers such as switches, diodes, inductors, electrolyticcapacitors, resistors, snubber networks, power supplies, batteries,logic circuitry, fuses, breakers, etc. This intimate contact may be madethrough one or more of: mechanical preload, direct contact, monolithicmaterial, heat-spreader, heat pipe, thermally conductive gel, foam,paste, epoxy, glue, filled polymer, metal. Some embodiments of heatgenerators, e.g., inductors may be disposed through a hole in a printedcircuit board such that flat surfaces of its bobbin are in intimatecontact with both sides of the cooling fin housing. Some embodimentssandwich substantially cylindrical heat generating components such asbatteries and electrolytic capacitors such that the components haveintimate thermal contact with the cooling fin housing along two tangentlines. In some such embodiments, an intermediary material having a highthermal conductivity may be interposed to enhance heat transfer from thenon-tangent sides of the cylinder. In some embodiments, the shape of thecooling fin housing may conform to the shape of the internal bodies togenerate an expanded area in intimate thermal contact for enhancedcooling and, in some cases, increased wetted area. In some embodimentsof the present invention a part of the cooling fin housing may be castor molded. In some embodiments a cooling fin housing component may becast, molded or conformally coated around one or more components. Someembodiments of cooling fin bodies further comprise features such assecondary fins disposed in the cooling fluid to increase the wettedarea. Some embodiments of cooling fin housings comprise a materialthickness sufficient to spread heat along the surface of the coolingbody. In embodiments, the circuitry housed in a cooling-fin body mayhave a ‘controlling dimension’ that sets a substantially uniform finoutside thickness. In some embodiments, this thickness is 5-50 mm, andpreferably 10-30 mm. An advantage of a smaller outside thickness may bereduced thermal diffusion length, while an advantage of a larger outsidethickness may be increased stiffness or mechanical strength. Someembodiments of the present invention substantially employ abattery/capacitor/and inductor controlling dimension of 12-25 mm.

Capacitor Module

Some electrolytic capacitors in accordance with the present inventionare disposed in removable modular arrays. Some such modules comprise aplurality of parallel and series-connected capacitors further comprisinga distributed or multi contact breakable connection to a printed circuitboard or mating connector.

Some embodiments of capacitor modules further comprise a charge-bleedresistor such that dangerous voltages are drained rapidly when a moduleis removed from equipment, but the resistor is disconnected when themodule is inserted. Some embodiments drain the capacitor module in 1ms-10 s and preferably 50 ms-2 s. Some embodiments employ a conductiveelastomer, rendered conductive via a fill material such as carbon,graphite, silver particles, etc. or via a conductive polymer backbone,to comprise this resistor. Some embodiments use the same resistor tolimit the rate of charge of capacitors on insertion by disposing theresistor such that the capacitor module first connects to power throughthe resistor, then when fully inserted, through a plurality oflow-resistance contacts.

Embodiments of capacitor modules distribute capacitors in a single widelayer so heat can be transferred efficiently from both sides of acooling-fin-body housing. Embodiments of contacts provide alow-inductance charge path across a wide module opening. Some suchelectrode embodiments comprise spring loaded conductors similar to thatknown in the art as ‘finger stock.’ Materials may include copper,beryllium copper, or high-conductance plated steels in the thicknessrange of 0.025-2 mm, preferably 0.1-0.5 mm. Some embodiments furthercomprise a corrosion resistant coating such as nickel or gold as knownin the art.

FIGS. 9A and 9B respectively show a side (900) and offset (920) view ofa two-bank-wide section of an arrayed bank of 2-series-connectedcapacitors in a capacitor module embodiment in an attachedconfiguration, wherein the capacitor module is making electrical contactwith a circuit board in a power module. Capacitor modules according toembodiments of the present invention may comprise arrays that are morethan two banks wide, with embodiments being in the range 2 to 64,increasing with the required capacity of the inverter. Some embodimentscomprise additional capacitors in series as known in the art to effect ahigher voltage holdoff. Insulators and some structural elements are notshown for clarity.

Elements 902 are electrolytic capacitors and element 904 is a thermallyconductive housing. An objective of this design is to maximize heattransfer per unit of housing material from the electrolytic capacitors.In some embodiments, the housing further comprises indentations tobetter conform to the shape of the electrolytic capacitor for betterthermal contact and increased wetted area for better heat transfer toambient.

Elements 906, 907, and 908 are sheet conductors disposed to minimizeinductance. These conductors may be isolated between one or more banksof capacitors within the module or common to all capacitor banks withinthe module. Element 910 is a circuit board of the power module insertedbetween ‘finger-stock’ electrodes 912 and 914. When inserted, aconductive pad on one side of the printed circuit board first makescontact with resistive electrode 916, which may comprise a filled orconductive elastomer. This forms an electrical connection that maygently allow charge redistribution between modules. As circuit board 910is inserted completely to the position shown in 900, contacts onopposite sides make compressive contact with the high-conductivityfinger stock electrodes. For clarity the board 910 is not shown in theview 920.

FIGS. 9C and 9D respectively show a side (940) and slightly offset (960)view of a capacitor module embodiment in a detached configuration,wherein the printed circuit board 910 is not compressing the fingerstock 914 and 912. As a result, the electrodes flexure relaxes and 914makes contact with resistive electrode 916 at location 942. In thisstate, energy within the capacitor module may be discharged in acontrolled, low-mechanical and electrical stress manner. Someembodiments of electrodes 916 are design such that the automaticdischarge time after a capacitor module is removed is of the order ofseconds or less so that a person removing the module is not exposed tostored energy or high voltage.

Stationary Assembly

Some embodiments of the present invention comprise a cooling-fin-bodypower module that is removably connected to an enclosure that issubstantially permanently installed herein called the ‘stationaryassembly’. The stationary assembly comprises an enclosure and mountinghardware and one or more openings to cables and cable conduits. Thestationary assembly may substantially comprise long-life andlow-maintenance componentry, conventional electrical wiring, breakers,switches, antennas, and the like. Some stationary assemblies may furthercontain technician replaceable components such as fuses, metal oxidevaristors and the like. Some embodiments of stationary assemblies mayfurther house an autotransformer. Some embodiments may further comprisean automated autotransformer connection switch. Some embodiments ofstationary assemblies comprise a feature such as a pipe or opening inthe back so that electrical cables including one or more of: DC stringcables, bypass cables, AC cables, communications cables can be neatlyrouted down the back side of the enclosure. Some embodiments ofstationary assemblies provide an opening on the bottom side throughwhich cables may pass into the interior of the stationary assembly. Somesuch assemblies provide a cowling or cover to protect and make the cableentry aesthetic. The interior of the stationary assembly may compriseone or more wire-terminal connectors as described herein. Some suchassemblies provide an opening or protrusion to allow one or more powermodule mating connectors to plug in.

Some embodiments comprise a connector disposed on one vertical side of astationary assembly some embodiments comprise two connectors disposed onopposite sides of a stationary assembly. Some embodiments comprise morethan one connector arrayed on one or two sides so that installed powermodules are arrayed like large parallel cooling fins, with a spacingbetween 1 and 50 times the cooling fin body thickness and preferablybetween 2 and 10 times this thickness.

Some comprise at least one mechanical latch to hold a power module inplace. Some comprise at least one conventional mechanical fastener, suchas a screw or bolt to hold a power module in place.

Some embodiments further comprise a mechanical shield outside theenvelope of a power module or modules. Some embodiments of shieldsprotect a power module from damage, e.g., from impact. Some embodimentsprotect against thermal burns, some shade a power module from directsunlight. Some shields are cosmetic and aesthetic.

Islanding Converter

Some embodiments of the present invention comprise a voltage-sourceinverter stage, herein an inverter stage that employs feedbacksubstantially to maintain a voltage waveform, that may be energized whenthe grid voltage is outside frequency or voltage specifications or whenthe grid is disconnected. In some embodiments, the inverter feedback maybe switched from a substantially current-feedback mode to asubstantially voltage-feedback mode, a mode comprising feedback derivedfrom a combination voltage signal and its derivatives and integrals, amode comprising feedback derived from a combination current signal andits derivatives and integrals, a mode comprising a combination of theprevious modes. In some embodiments, this switching is performed by oneor more of: an analog switch, a tristate-able I/O line, a transistorcircuit, an op-amp circuit, microcontroller firmware, changing weightingvariables in firmware, changing algorithms in firmware, changingsubroutines in firmware as known in the art.

In some embodiments the inverter stage may operate to feed a grid signalto a second inverter that is within the second inverter operatinglimits. In some embodiments this provides for a second inverter to beoperated to increase the power output of a system in a master-slavearrangement wherein the first inverter is the master and the secondinverter is the slave as known in the art. Some embodiments comprise aplurality of slave inverters. Some embodiments may further comprise aninertial load/generator such as a flywheel to resist rapid voltagevariations from current transients and surges. Some embodiments energizea flywheel only when supplying power during an outage.

Some embodiments of circuits controlling the discharge of batteries maycontrol the output power to vary slow enough not to interfere with amaximum power-point tracking algorithm. In some embodiments thecontroller detects a voltage, current, or combination waveformassociated with a power-point optimization sequence initiated by aninverter and maintains a substantially constant power discharge duringthis interval. In some embodiments, the Balancer and batterycharge-discharge circuit feeds an external (non-integrated) inverter.

EXAMPLES

In the following sections, further exemplary embodiments are provided.

Example 1 may include an inverter system comprising a battery module, asolar panel, and a battery charge control circuitry coupled to thebattery module and the solar panel, the battery charge control circuitryto control a rate of discharge of the battery module to be applied tothe solar panel and to cause the battery module to be charged.

Example 2 may include the inverter system of example 1, wherein thebattery charge control circuitry includes a first switch coupled to abuck converter, the first switch to control the rate of discharge of thebattery module, and a second switch coupled to boost circuit, the secondswitch to cause the battery module to be charged.

Example 3 may include the inverter system of example 1, wherein thebattery charge control circuitry includes bus circuitry coupled to thebattery module and the solar panel, and an optimizer coupled to the buscircuitry, the optimizer to draw power from the bus circuitry andprovide power to a load.

Example 4 may include the inverter system of example 3, wherein the loadcomprises an inverter.

Example 5 may include the inverter system of example 1, wherein thesolar panel is a first solar panel, wherein the inverter system furthercomprises a second solar panel coupled in series with the first solarpanel, and wherein a bypass cable couples the battery charge controlcircuitry between the first solar panel and the second solar panel.

Example 6 may include the inverter system of example 1, furthercomprising an inverter coupled to the battery charge control circuitry,wherein the inverter is switchable between current-feedback andsubstantially voltage-feedback control.

Example 7 may include an inverter system, comprising a stationary unit,a detachable power module coupled to the stationary unit, a detachablecapacitor module coupled to the detachable power module, and one or moredetachable battery modules coupled to the detachable power module.

Example 8 may include the inverter system of example 7, wherein thedetachable power module is housed in a cooling-fin geometry, whereinheat-generating devices of the detachable power module are in intimatethermal contact with interior-facing sides of two thermally conductivesheets disposed on opposite sides of the heat-generating devices, andwherein exterior-facings sides of the two thermally conductive sheetsare disposed to facilitate heat transfer to a fluid.

Example 9 may include the inverter system of example 8, wherein thefluid is naturally convecting air, and wherein the two thermallyconductive sheets are disposed with a substantially vertical exteriorsurface plane.

Example 10 may include a battery module comprising an array ofbatteries, the array of batteries being singly stacked, and a batterycharge board coupled to the array of batteries by one or moreconnections, the battery charge board having one or more cell bypasscircuits to bypass one or more cells of the array of batteries when theone or more cells reach a full-charge state.

Example 11 may include the battery module of example 10, wherein eachbattery within the array of batteries includes an AC-coupled connectionto a common full-discharge indicator line.

Example 12 may include the battery module of example 10, the batterymodule further comprises auxiliary connections to couple to batterycharge control circuitry, wherein the battery module is to be physicallyseparated from the battery charge control circuitry by a corrugatedisolator.

Example 13 may include the battery module of example 12, wherein thebattery charge board is to communicate to the battery charge controlcircuitry one or more of an end of charge, end of discharge, cell type,temperature, charge profile, charge history, state of charge, serialnumber, date of manufacturing, charge/discharge limits, or cellchemistry of the one or more cells.

Example 14 may include a switch comprising a magnetic attachment forattaching a plate of the switch to a panel surface, one or more fingersfor actuation of a throw of the switch, a motor to cause the one or morefingers to actuate the throw to change a state of the switch, a forceamplification stage coupled to the motor to amplify an amount of forceproduced by the motor to cause the one or more fingers to actuate, amotor-current-sensing circuit to sense a current of the motor, and amicrocontroller to determine whether to set the switch to a connectedstate or disconnected state based on the current.

Example 15 may include the switch of example 14, wherein the motor is agear motor.

Example 16 may include the switch of example 14, wherein the forceactuation stage comprises a planetary gear reduction stage, a standardgear reduction stage, a worm gear, or a lead screw.

Example 17 may include the switch of example 14, further comprising alead screw to be utilized for overcoming a magnetic force of themagnetic attachment to remove the plate from the panel surface.

Example 18 may include the switch of example 14, further comprising acommunication module to establish a communication link to a smart meter.

Example 19 may include the switch of example 14, further comprising acapacitively coupled AC waveform voltage sensing circuit, themicrocontroller to synchronize actuation of the throw with an ACwaveform sensed by the capacitively coupled AC waveform voltage sensingcircuit.

Example 20 may include the switch of example 14, wherein themicrocontroller is to implement a motion algorithm to infer a state ofthe switch nonintrusively.

Example 21 may include the switch of example 20, wherein themicrocontroller is to cause a finger, of the one or more fingers, to bemoved, sense a current associated with movement of the finger, and inferthe state of the switch based on comparison of the current with asetting.

Example 22 may include a balancer-based power optimizer furthercomprising a battery charge controller.

Example 23 may include the power optimizer of claim 22 furthercomprising a battery module.

Example 24 may include an array of power optimizers of claim 23 at leastone of which is connected between two panels by a bypass cable.

Example 25 may include a hybrid inverter system comprising the array ofpower optimizers of claim 24 and an inverter that is switchable betweencurrent-feedback and substantially voltage-feedback control.

Example 26 may include a hybrid inverter system comprising an assemblyof a stationary element, a detachable power module, a detachablecapacitor module, and at least one detachable battery module.

Example 27 may include a hybrid inverter system according to claim 26wherein a detachable module is housed in a cooling-fin geometry whereinheat-generating devices are in intimate thermal contact withinterior-facing sides of two thermally conductive sheets disposed onopposite sides of the heat-generating devices and wherein theexterior-facing sides of the sheets are disposed to facilitate heattransfer to a fluid.

Example 28 may include the inverter system of claim 27 wherein the fluidis naturally convecting air and the sheets are disposed with asubstantially vertical exterior surface plane.

Example 29 may include a battery module comprising a singly stackedarray of batteries, each further comprising a connection to a batterymanagement board having an individual cell bypass/charge dump circuitthat is activated when a cell reaches a full-charge state, each furthercomprising an AC-coupled connection to a common full-discharge indicatorline.

Example 30 may include an array of battery modules of claim 29, eachconnected to the power optimizer of claim 22 physically separated by acorrugated isolator.

Example 31 may include an automated switch/breaker controller comprisinga gearmotor, leadscrew, finger, magnetic attachment, motorcurrent-sensing circuit, and microcontroller with non-volatile memory.

Example 32 may include an automated switch/breaker controller of claim31 further comprising a communication link to a Smart Meter.

Example 33 may include an automated switch/breaker controller of claim31 further comprising a capacitively coupled AC waveform voltage sensingcircuit.

Example 34 may include an automated switch/breaker controller of claim31 further comprising a motion algorithm that moves an actuator fingerwhile sensing current, compares the current to a setting, then uses thiscomparison to infer the state of a switch/breaker nonintrusively.

What is claimed is:
 1. A hybrid inverter system comprising: abalancer-based power optimizer including a battery charge controller; anarray of power optimizers, wherein the balancer-based power optimizer isa first power optimizer and the array of power optimizers includes thefirst power optimizer, and wherein at least one power optimizer withinthe array of power optimizers is connected between two panels by abypass cable; and an inverter that is switchable betweencurrent-feedback and substantially voltage-feedback control.
 2. Thehybrid inverter system of claim 1, wherein the balancer-based poweroptimizer further comprises a battery module.
 3. A hybrid invertersystem comprising an assembly of a stationary element, a detachablepower module, a detachable capacitor module, and at least one detachablebattery module.
 4. The hybrid inverter system of claim 3, wherein adetachable module is housed in a cooling-fin geometry, whereinheat-generating devices are in intimate thermal contact withinterior-facing sides of two thermally conductive sheets disposed onopposite sides of the heat-generating devices, and whereinexterior-facing sides of the two thermally conductive sheets aredisposed to facilitate heat transfer to a fluid.
 5. The hybrid invertersystem of claim 4, wherein the fluid is naturally convecting air and thetwo thermally conductive sheets are disposed with a substantiallyvertical exterior surface plane.